1. Field of the Invention
This invention relates to a linear guide device, and in particular to a linear guide device in which the working of ball return holes and the assembly of the entire device have become easy.
2. Description of the Prior Art
A linear guide device includes an axially extending rail and a saddle-shaped (C-shaped) bearing movably mounted thereon through a number of balls. As the bearing moves on the rail, the balls roll in a ball rolling grooves formed between the rail and the bearing oppositely and come to an end portion of the bearing. Therefore, usually, a pair of end caps for circulating (U-turning) the balls are attached to the opposite ends of the bearing and an axial hole for returning the balls U-turned by the end caps of the opposite end portion of the bearing is formed in each side of the bearing.
Said ball return hole has heretofore been formed by forming an elongated circular hole in the bearing body by the use of a drill. However, where the diameter of the hole is small, the drill is readily damaged and the working of the hole requires a long time and moreover, the holes is bent or otherwise deformed. All these lead to low working accuracy. Also, the balls must be inserted into this ball return hole through the openings at the opposite ends thereof, and this has means cumbersomeness of the incorporation of the balls.
In order to eliminate such inconveniences, the applicant has disclosed, in Japanese Utility Model Application No. 157023/1983, a technique of forming concave grooves in the opposite outer sides of the bearing, closing the concave grooves by closure members and thereby forming ball return holes.
According to this technique, however, screw members or the like are used to attach the closure members to the bearing body, and this has led to a problem that the operation of attaching the closure members, that is, the formation of the return hole, is cumbersome.